Chinese scientists have transmitted information from geostationary orbit to Earth at a speed of 1 Gbps, five times faster than Starlink. To do this, they used a laser with a power of only 2 watts. This is reported by the South China Morning Post.
The experiment was conducted at the Lijiang Observatory in southwest China using a 1.8-meter telescope aimed at the satellite at an altitude of 36,705 km. Inside the telescope, 357 micromirrors were placed to correct wavefront distortions caused by atmospheric turbulence.
According to the scientists, previous approaches — adaptive optics (AO) and multimode reception (MDR) — did not provide stable results individually. The team from Beijing University of Posts and Telecommunications combined these methods, which allowed to significantly improve the signal quality even at very low power.
Data transmission took place over a multimode optical channel, where a special "path-picking" algorithm selected the three strongest signals from eight basic channels in real time. They were merged into one, minimizing losses.
The test results showed that the probability of receiving a usable signal increased from 72% to 91.1%. This is critical for systems where delays and errors are unacceptable, such as in military or interplanetary communications.
In 2020, China already set a record by transmitting data at a speed of 10 Gbps from the Shijian-20 satellite. However, the exact characteristics of that mission remain classified. According to some reports, American satellites even tried to spy on Shijian-20, but the Chinese device changed its trajectory to avoid observation.